Dispersal polymorphism and physiological condition of males and females in the ant, Formica truncorum

This study deals with dispersal behavior of sexuals and intraspecificvariation in queen numbers. The specific questions are: (1)Is there an association between male and female dispersal behaviorand the number of queens in a colony? (2) Is there an associationbetween individual behavior and physiological condition? (3)Do males and females from monogyne (one queen per colony) andpolygyne (several functional queens per colony) colonies differwith respect to size, weight, and physiological condition? Theresults show that both males and females are more prone to dispersein monogyne than in polygyne colonies. Moreover, males and femalesof both monogyne and polygyne colonies show dispersal polymorphism,suggesting that an increased tendency of reproductive femalesto stay in the maternal colony may cause monogyne colonies toswitch to polygyny. The propensity to disperse is associatedwith the physiological condition of individuals. Larger andheavier females containing more fat and glycogen preferentiallydisperse, whereas smaller ones with less fat and glycogen moreeasily dealate and mate without a previous nuptial flight. Maledispersal correlates positively to larger size and higher levelsof glycogen; fat contents do not increase during maturation.The females produced in monogyne colonies are larger, heavier,and contain more fat and glycogen than those produced in polygynecolonies. The males produced in monogyne colonies have relativelylonger wings and are heavier than those produced in polygynecolonies. However, there are no differences in size and fatcontents between males from monogyne and polygyne colonies.     

Ultrastructure of the milk fat globule membrane with and without triglyceride

Summary The primary milk fat globule membrane (MFGM) around freshly secreted milk fat globules consists of a unit membrane separated from the triglyceride core by a dense material. This dense material may widen to include cytoplasmic organelles or may form small blebs. Preincubation and fixation of the globules at temperatures between 4° C and 60° C has no effect on the width or appearance of the dense material. Isolated MFGM profiles show structures identical to those found on intact globules. The dense material on the isolated MFGM profiles is unaffected by extractions which remove essentially all the triglyceride present in the pellets of MFGM.The structure of the primary MFGM is therefore independent of any triglyceride content and the earlier suggestions that the dark material represented a triglyceride layer of high melting point adsorped during cooling of the globules after milking are not supported by the work described in this paper.     

Preface

The vector of Chagas' disease, Rhodnius prolixus, feeds exclusively on blood. The blood meals are slowly digested, and these insects wait some weeks before the next meal. During the life of an insect, energy‐requiring processes such as moulting, adult gonadal and reproductive growth, vitellogenesis, muscular activity, and fasting, lead to increased metabolism. Carbohydrates are a major source of energy and their mobilization is important. We determined the amounts of glycogen, trehalose, and glucose present in the fat body and/or hemolymph of adult males of R. prolixus and recorded the processes of accumulation and mobilization of these carbohydrates. We also tested our hypothesis that these processes are under endocrine control. The amount of glycogen in the fat body progressively increased until the fourth day after feeding (from 9.3±2.2 to 77. 3±7.5 µg/fat body), then declined to values around 36.3±4.9 µg/fat body on the fifteenth day after the blood meal. Glycogen synthesis was eliminated in decapitated insects and head‐transplanted insects synthesized glycogen. The amount of trehalose in the fat body increased until the sixth day after feeding (from 16. 6±1.7 to 40. 6±5.3 nmol/fat body), decreased abruptly, and stabilized between days 7 and 15 at values ranging around 15–19 nmol/fat body. Decapitated insects did not synthesize trehalose after feeding, and this effect was reversed in head‐transplanted insects. The concentration of trehalose in the hemolymph increased after the blood meal until the third day (from 0.07±0.01 to 0.75±0.05 mM) and at the fourth day it decreased until the ninth day (0.21±0.01 mM), when it increased again until the fourteenth day (0.79±0.06 mM) after the blood meal, and then declined again. In decapitated insects, trehalose concentrations did not increase soon after the blood meal and at the third day it was very low, but on the fourteenth day it was close to the control values. The concentration of glucose in the hemolymph of untreated insects remained low and constant (0.18±0.01 mM) during the 15 days after feeding, but in decapitated insects it progressively increased until the fifteenth day (2.00±0.10 mM). We recorded the highest trehalase activity in midgut, which was maximal at the eighth day after feeding (2,830±320 nmol of glucose/organ/h). We infer that in Rhodnius prolixus, the metabolism of glycogen, glucose, and trehalose are controlled by factors from the brain, according to physiological demands at different days after the blood meal. © 2009 Wiley Periodicals, Inc.     

Comparative analysis of zygospore transcripts during early germination in Chlamydomonas reinhardtii

The unicellular green alga Chlamydomonas reinhardtii has a haplontic life cycle, and forms diploid zygotes for reproduction. The zygospore, a sporulating zygote, begins germination in response to light signals, generating haploid progenies and inducing several cell-biological events; e.g., DNA synthesis and meiotic division, successively. Their regulatory mechanisms remain largely unknown, so we focused on the early stages of germination and analyzed the dynamics of gene expression associated with the germination process. The gene expression levels of zygospores at 1 and 6 h after light exposure were analyzed by a next-generation sequencing platform, the 454 GS Junior. At 6 h, the photosynthesis pathway, including its antenna proteins and two methionine metabolism-related genes (methionine synthase and sulfite reductase), were up-regulated compared to 1 h after light exposure. Meanwhile, three uncharacterized genes that contained an antibiotic biosynthesis monooxygenase domain and an HSP20/alpha crystallin family protein were specifically expressed at 1 h after light exposure. These gene expressions were also verified by quantitative real-time PCR analysis. These results suggest that the photosynthesis and methionine synthesis pathways, both of which occur in the chloroplast, are activated in zygospores at around 6 h after light exposure, and that some polyketides and/or a small heat shock protein may be related to the initiation of zygospore germination.     

老龄化引起的脂肪组织重新分布与代谢功能障碍

在生物的一生中,脂肪总量以及脂肪组织分布变化很大。在老龄阶段,脂肪组织从皮下转移到腹部内脏、骨髓、肌肉、肝脏和其他的异位位点,引发脂肪功能障碍。脂肪的异位沉积增加了代谢综合征发生的危险。随着年龄的增加,前体脂肪细胞的增殖和分化能力下降,致使机体持续处于游离脂肪酸过多所产生的脂毒性状态。前体脂肪细胞和巨噬细胞以部位依赖的方式影响着年龄相关的脂肪组织炎症。脂肪组织炎症进一步导致老年人脂肪生成减少,脂毒性增加,细胞应激通路激活,这加剧了前体脂肪细胞和免疫细胞的炎症反应,最终导致系统功能障碍。该文就老龄化引起的脂肪组织重新分布和代谢功能障碍研究进展作一简要综述。     

Molecular characterization,transcriptional regulation and association analysis with carcass traits of porcine TCAP gene

TCAP (also known as titin-cap or telethonin) is one of the titin interacting Z-disk proteins involved in the regulation and development of normal sarcomeric structure. In this study, we cloned the cDNA and promoter sequences of porcine TCAP gene, which contained a 504 bp full-length coding region. Quantitative real-time PCR (qRT-PCR) analyses showed that porcine TCAP was highly expressed in the skeletal muscle, heart, and kidney. During postnatal muscle development, TCAP expression was down-regulated from 30 days to 120 days in Large White and Meishan pigs. One single nucleotide polymorphism c.334G>A in exon 2 of the TCAP gene was identified and detected by allele-specific primer-polymerase chain reaction (ASP-PCR). Association analysis revealed that the polymorphism had significant associations (P < 0.05 and P < 0.01) with some carcass traits. Analysis of the porcine TCAP promoter in different cell lines demonstrated that it is a muscle-specific promoter. In addition, we found that the porcine TCAP promoter can be activated by MyoD, MyoG and MEF2 in myotubes, which indicated that TCAP may play a role in the regulation of porcine skeletal muscle development. These findings provide useful information for the further investigation of the function of TCAP in porcine skeletal muscle.     

Identification of splice variants,expression analysis and single nucleotide polymorphisms of the PRMT2 gene in dairy cattle

Protein arginine N-methyltransferase 2 (PRMT2), also named HRMT1L1, belongs to the Bovine Protein arginine N-methyltransferase (PRMT) genes which are involved in the immune response. To explore the variability of the PRMT2 gene and resistance to mastitis in cows, splice variant (SV), and single nucleotide polymorphisms (SNPs) were identified in this study. A SV (PRMT2-SV) lacking exon 7 (98-bp) of the PRMT2 gene was found in healthy and mastitis-infected mammary gland tissues. Two of four SNPs were significantly associated with bovine milk yield and protein content. Further, we estimated the relative expression of PRMT2-SV in the mammary gland tissue of dairy cattle by using quantitative real-time polymerase chain reaction. The result showed that expression of the PRMT2-SV mRNA was significantly upregulated 4.02-fold (p < 0.05) in infected mammary tissues (n = 5) compared to healthy tissues (n = 5). Our findings reveal that PRMT2-SV may play an important role in mastitis resistance in dairy cattle. The SNPs may be used as a possible candidate SNPs for marker-assisted selection and management in Chinese Holstein cattle.     

Effect of finishing period length with α-tocopherol supplementation on the expression of vitamin E-related genes in the muscle and subcutaneous fat of light lambs

The aim of this study was to investigate how different finishing period lengths with α-tocopherol supplementation or alfalfa grazing affect mRNA expression levels of genes related to vitamin E metabolism in L. thoracis (LT) muscle and subcutaneous fat (SF) from lambs of the Rasa Aragonesa breed. Indoors, concentrate-fed light lambs (n = 48) were supplemented with 500 dl-α-tocopheryl acetate/kg concentrate for an average finishing period length of 0 (C), 10.7 (VE10d), 21.2 (VE20d) and, 32.3 (VE30d) days before slaughtering. Simultaneously, 8 lambs with their dams were alfalfa-grazed. The α-tocopherol affected in a short-term the expression of genes in LT muscle (ABCA1, LPL, APOE, and SREBP1) and SF (ABCA1, SCARB1, LPL, and PPARG). On the contrary, PPARA gene expression showed a long-term α-tocopherol effect because the highest levels of PPARA mRNA were found in the VE30d.     

Detection of SNPs in the TBC1D1 gene and their association with carcass traits in chicken

TBC1D1 plays an important role in numerous fundamental physiological processes including muscle metabolism, regulation of whole body energy homeostasis and lipid metabolism. The objective of the present study was to identify single nucleotide polymorphisms (SNPs) in chicken TBC1D1 using 128 Erlang mountainous chickens and to determine if these SNPs are associated with carcass traits. The approach consisted of sequencing TBC1D1 using a panel of DNA from different individuals, revealing twenty-two SNPs. Among these SNPs, two polymorphisms (g.69307744C>T and g.69307608T>G) of block 1, four polymorphisms (g.69322320C>T, g.69322314G>A, g.69317290A>G and g.69317276T>C) of block 2 and four polymorphisms of block 3 (g.69349746G>A, g.69349736C>G, g.69349727C>T and g.69349694C>T) exhibited a high degree of linkage disequilibrium in all test populations. An association analysis was performed between the twenty-two SNPs and seven performance traits. SNPs g.69307744C>T, g.69340192G>A and g.69355665T>C were demonstrated to have a strong effect on liveweight (BW), carcass weight (CW), semi-eviscerated weight (SEW) and eviscerated weight (EW) and g.69340070C>T polymorphism was related to BW, SEW and BMW in chicken populations. However, for the other SNPs, there were no significant correlations between different genotypes and carcass traits. Meanwhile, haplotype CT–TG of block 1 and combined genotype AG–TT–AC–CT of block 3 were significantly associated with BW, CW, SEW and EW. Overall, our results provide evidence that polymorphisms in TBC1D1 are associated with carcass traits and would be a useful candidate gene in selection programs for improving carcass traits.